The MLS was the proposed land based update for ILS. MLS allowed for variable glideslopes and curved approaches and was much less critical of siting criteria. Improvements in approach aids based on GPS have limited the adoption of MLS.
The archive contains a lot of photographs on MLS and its flight, ground testing and calibration programme.
Doppler MLS landing trials at KJEVIK airport, Kristiansand, Norway
DMLS TRIALS AT GATWICK
The Doppler MLS elevation array and transmitter, developed and manufactured by Plessey, installed for trials at Gatwick. In the background, he HS748 belongs to the Royal Aircraft Establishment used during trials is seen on final approach for an automatic landing. The tented enclosure provided temporary housing for the test equipment.
DMLS trials Manchester Airport
The Doppler MLS azimuth array and transmitter, developed and manufactured by Plessey, installed for flight trials at Manchester Ringway Airport. The picture shows a Royal Aircraft Establishment Andover on completion of an azimuth test flight using Doppler MLS.
The prototype MLS evaluation system manufactured by Plessey, installed at the Royal Aircraft Establishment Bedford where it successfully underwent flight trials. The photograph shows the antennae redome removed to show the form of the radiating aperture. The height of the production antennae will be approximately 12 feet as compared to the 24 feet of the prototype.
Doppler MLS trials at Bern (Belp) Airport.
A Royal Aircraft Establishment Andover is pictured making an automatic landing on the narrow 30 metre runway at Bern (Belp) Airport in overcast conditions under landing guidance from the Plessey Doppler MLS installed. In the foreground is the DLMS elevation aerial and in the distance is a steep hill rising sharply to 1100 feet which would normally pre-empt safe landing guidance from conventional navigational aids.
The mountainous terrain on approach to Belp Airport and the close proximity to the airport of buildings, trees and pylons are clearly shown in the photos. Despite these forbidding surroundings over 50 fully automatic landings were made using DMLS. The black column in the foreground is rhe elevation array of the DMLS.
The operator is using a Telecroscope which measures the actual flight path of the aircraft for comparison with the Doppler data as recorded in the aircraft’s trials equipment.
Doppler MLS at Teheran (Mehrabad) Airport.
Over 70 approaches including autolands and segmented approaches were carried out recently by a Royal Aircraft Establishment HS748 during recent performance trials. The DMLS azimuth antennaes were installed and in operation within the usual 48 hours on the site which as shown in the photo had undergone only mimimum preparation.
DMLS Elevation transmitter
MLS performance monitor on right
I’ve added some additional photos of CAFU aircraft from Barry Davidson.
I can’t remember whether MJ was on a seasonal lease to Danair or this is the aircraft after CAFU disposed of it? It was I seem to remember it was unusual in that MJ was fully fitted out in airline configuration inside unlike the other 748s. Looking on line……..
“HS748 G-ATMJ CAA Dec-72 Jul-78” and “This 748, G-ATMJ was a 44 seat aircraft which gave CAA crews a more up-to -date environment in which to fly (than the DH Dove -ed). It was also used for educational flights by Essex Schools, carried Members of the European Parliament to Luxembourg and Strasbourg as well as being leased to Dan Air at weekends. Airway reported that it had carried 42,000 passengers (4,000 of them children).”
MJ also flew with British Airways, Autair International, British Air Ferries and Emerald Airways.
Airspeed Consul G-AJXF
Avro Anson G-AHIH 1949
de Havilland Chipmunk G-ANWB
DH Dove G-ANOV
Hunting Percival Prince G-APMO (lower shot)
Avro 748 G-AVXI